feat: 流式数据中自动滚动控制实现

src/hooks/useAutoScroll.ts

@@ -0,0 +1,124 @@
+import { ref, onMounted, onUnmounted } from 'vue';
+
+/**
+@example
+1. 页面引入该hooks, 并调用useAutoScroll()，返回三个值：canAutoScroll, contentRef, contentScrollFN
+import { useAutoScroll } from '@/hooks/useAutoScroll';
+const { canAutoScroll, contentRef, contentScrollFN } = useAutoScroll();
+  
+2. 需要配置自动滚动的dom加上contentRef属性(contentRef名称不能修改，必须匹配)，并监听scroll调用contentScrollFN()方法
+<div
+    class="wordbox"
+    ref="contentRef"
+    @scroll="contentScrollFN"
+>
+</div>
+
+3. 在请求流式数据时，设置canAutoScroll为true
+
+### 注意事项
+滚动的dom样式要求
+.wordbox {
+    overflow-y: auto;
+    overflow-x: hidden;
+    scrollbar-width: none;
+    word-break: break-all;
+}
+.wordbox::-webkit-scrollbar {
+    display: none;
+}
+ */
+export function useAutoScroll() {
+    let prescrollHeight = 0;
+    let touchStartPointY = 0;
+    const canAutoScroll = ref(false);
+    const contentRef = ref(null);
+
+    const contentScrollFN = () => {
+        if (canAutoScroll.value === true) {
+            return;
+        }
+        // +10 这里是一个缓冲区，只要快到底部就触发自动滚动
+        if (contentRef.value.scrollTop + contentRef.value.clientHeight + 10 >= contentRef.value.scrollHeight) {
+            console.log('设置开始自动滚动');
+            canAutoScroll.value = true;
+        }
+    };
+
+    const observeScrollFN = () => {
+        const observe = new MutationObserver((mutations) => {
+            if (!contentRef.value || !canAutoScroll.value) {
+                return;
+            }
+            mutations.forEach((mutation) => {
+                if (mutation.type !== 'childList') {
+                    return;
+                }
+
+                if (prescrollHeight != contentRef.value.scrollHeight) {
+                    contentRef.value.scrollTo({
+                        top: contentRef.value.scrollHeight,
+                        behavior: 'smooth',
+                    });
+                    prescrollHeight = contentRef.value.scrollHeight;
+                }
+            });
+        });
+
+        const config = {
+            childList: true,
+            subtree: true,
+        };
+        observe.observe(contentRef.value, config);
+    };
+
+    const touchstartFN = (event) => {
+        touchStartPointY = event.targetTouches[0].pageY;
+    };
+
+    const touchmoveFN = (event) => {
+        if (event.targetTouches.length > 1) {
+            return;
+        }
+        // event.targetTouches[0].pageY - touchStartPointY > 0 即为内容往上滑动
+        // 5这里也是缓冲区
+        if (canAutoScroll.value === true && event.targetTouches[0].pageY - touchStartPointY > 5) {
+            canAutoScroll.value = false;
+        }
+    };
+
+    const touchendFN = () => {
+        touchStartPointY = 0;
+    };
+
+    const wheelFN = (event) => {
+        /** 修复mac下whell触发后惯性继续触发问题 */
+        if (event.deltaY < 0) {
+            // console.log('向上滚动');
+            canAutoScroll.value = false;
+        } else if (event.deltaY > 0) {
+            // console.log('向下滚动');
+        }
+    };
+
+    onMounted(() => {
+        observeScrollFN();
+        window.addEventListener('touchstart', touchstartFN);
+        window.addEventListener('touchmove', touchmoveFN);
+        window.addEventListener('touchend', touchendFN);
+        window.addEventListener('wheel', wheelFN);
+    });
+
+    onUnmounted(() => {
+        window.removeEventListener('touchstart', touchstartFN);
+        window.removeEventListener('touchmove', touchmoveFN);
+        window.removeEventListener('touchend', touchendFN);
+        window.removeEventListener('wheel', wheelFN);
+    });
+
+    return {
+        canAutoScroll,
+        contentRef,
+        contentScrollFN,
+    };
+}

src/views/demo/sseFetch.vue

@@ -15,40 +15,37 @@
         </div>
         <div
             class="wordbox"
-            ref="containerRef"
+            ref="contentRef"
+            @scroll="contentScrollFN"
         >
-            <span
+            <div
                 id="content"
                 v-html="content"
-            ></span>
+            ></div>
         </div>
     </base-container>
 </template>
 
 <script setup>
-import { ref, nextTick } from 'vue';
+import { ref } from 'vue';
 import { fetchEventSource } from '@microsoft/fetch-event-source';
+import { useAutoScroll } from '@/hooks/useAutoScroll';
+const { canAutoScroll, contentRef, contentScrollFN } = useAutoScroll();
 
 const content = ref('');
 const controller = ref(null);
 
 const updateContent = (event) => {
-    console.log(event);
+    content.value += event.data;
-    console.log('sse收到消息');
-    content.value += event.data + '<br/>';
-    console.log(content.value, 'content内容');
     if (event.data === 'End') {
         /**
          * 注释部分为前端手动关闭sse连接的实现
-         * 这里不受冻关闭原因是@microsoft/fetch-event-source这个框架可以正确检测后段服务端是否关闭了连接，所以不需要手动关闭
+         * 这里不手动关闭原因是@microsoft/fetch-event-source这个框架可以正确检测后段服务端是否关闭了连接，所以不需要手动关闭
          * 浏览器原生new EventSource()方法无法检测后端服务端是否关闭连接，所以需要手动关闭(每次后段关闭都会进onerror事件)
          * 具体请看另外一个demo sseNative.vue
          */
         // handleClose();
     }
-    nextTick(() => {
-        scrollToBottom();
-    });
 };
 
 const handleError = (event) => {
@@ -58,19 +55,15 @@ const handleError = (event) => {
 
 const handleClose = () => {
     console.log('sse关闭');
-    // controller.value.abort();
+    controller.value.abort();
-};
-
-const containerRef = ref(null);
-const scrollToBottom = () => {
-    containerRef.value.scrollTop = containerRef.value.scrollHeight;
 };
 
 const handleSend = () => {
+    canAutoScroll.value = true;
     controller.value = new AbortController();
     const signal = controller.value.signal;
     /** @microsoft/fetch-event-source该框架支持POST方法，并且支持传参 */
-    fetchEventSource('http://localhost:3000/events', {
+    fetchEventSource('http://192.168.197.120:3000/events', {
         method: 'POST',
         body: JSON.stringify({
             question: '你好，我是小雅，请问有什么可以帮助您？',
@@ -87,11 +80,19 @@ const handleSend = () => {
 <style lang="scss" scoped>
 .wordbox {
     width: 100%;
-    height: 100%;
+    height: 200px;
-    overflow: auto;
+    position: relative;
+    overflow-y: auto;
+    overflow-x: hidden;
     padding: 20px;
     border: 1px solid #ccc;
     margin: 20px 0;
     border-radius: 5px;
+    scrollbar-width: none;
+    word-break: break-all;
+}
+
+.wordbox::-webkit-scrollbar {
+    display: none; /* 隐藏滚动条 */
 }
 </style>